THE APPLICATION of an occlusive tourniquet to a limb is common practice when surgical operations are performed on the extremities. The presence of the inflated tourniquet presents problems for the anesthesiologist who wishes to improve operating conditions by providing muscular relaxation under general anesthesia. The occlusion of the arterial supply to the operative area prevents systemically administered muscle relaxants from reaching the desired site of action. Large doses of long-acting muscle relaxants may be administered prior to the inflation of the tourniquet. This technique, however, requires assisted or controlled ventilation and may necessitate endotracheal intubation, which is ordinarily not required for this type of surgery. Muscular relaxation can also be produced by deep general or regional anesthesia. The muscular relaxation of deep general anesthesia is accompanied by respiratory and circulatory depression and may cause various operative and postoperative complications.
The injection of muscle relaxants into a large artery proximal to